Fundamental details of the system for outflow of aqueous humor remain unknown, yet more knowledge seems vital to full comprehension of the pathogenesis of various types of glaucoma, and to potential improve-ments in treatment of glaucoma, or possibly its prevention. To learn more about these potentially vital details, we propose to examine inten-sively certain of the properties of the endothelial cells of the corneoscleral trabecular meshwork, which are most intimately involved in aqueous outflow and which may well be highly influential in control of intraocular pressure. We propose in cats and monkeys to investigate the proliferative and synthetic capabilities of these cells, following quantitatively by auto-radiography and electron microscopy their mitosis and the synthesis and deposition of glycosaminoglycans, collagen and glycoproteins by these cells. We propose to perform related histochemical studies on animal eyes and also on excised human eyes, both normal and glaucomatous, to determine the location and concentration of specific varieties of the glycosaminoglycans. In animals we will investigate the immediate and long-term fate of trabecular endothelial cells after injection of inert particles into the anterior chamber, and after exposure to degradative enzymes and surgical injury. Later, we will establish trabecular cells in tissue culture, where their synthetic activity and responses to iris pigment particles, drugs and poisons will be studied. Taking advantage of the autoradiographic and histochemical tech-niques that are established for the endothelial cell studies, we will perform a separate study utilizing tritiated drugs to identify probable sites for carbonic anhydrase inhibitors.